The maximum term of options granted for a type of share-based payment arrangement that existed at any time during the period.

No definition available.

+ Details

Name:	aciu_MaximumTermOfOptionsGrantedForShareBasedPaymentArrangement
Namespace Prefix:	aciu_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of equity-based instrument plans approved by the entity.

+ References

No definition available.

+ Details

Name:	aciu_NumberOfEquityBasedInstrumentPlans
Namespace Prefix:	aciu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	aciu_ShareBasedPlansOutstandingAbstract
Namespace Prefix:	aciu_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

For vesting requirements for a type of share-based payment arrangement that existed at any time during the period, this element represents the period which an employees right to exercise and award in no longer contingent on satisfaction of a service condition.

+ References

No definition available.

+ Details

Name:	aciu_VestingRequirementsForShareBasedPaymentArrangementAwardVestingPeriod
Namespace Prefix:	aciu_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of share options granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2016-01-13
-Paragraph 45
-Subparagraph b
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2016-03-30&anchor=para_45_b_ii&doctype=Standard
-URIDate 2016-03-31

+ Details

Name:	ifrs-full_NumberOfShareOptionsGrantedInSharebasedPaymentArrangement
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=aciu_StockOptionPlanAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=aciu_StockOptionPlanBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=aciu_StockOptionPlanC1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=aciu_Two016ShareOptionAndIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_KeyManagementPersonnelOfEntityOrParentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=aciu_EmployeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Share-based compensation, Plans Outstanding (Details)	12 Months Ended
Share-based compensation, Plans Outstanding (Details)	Dec. 31, 2017 shares Plan	Dec. 31, 2016 shares	Dec. 31, 2015 shares
Share-based compensation [Abstract]
Number of equity-based instrument plans \| Plan	4
Share-based plans outstanding [Abstract]
Number of options awarded (in shares)	276,766	285,250	223,250
Contractual life of options	10 years
Stock Option Plan A [Member]
Share-based plans outstanding [Abstract]
Number of options awarded (in shares)	362,750
Contractual life of options	15 years 6 months
Stock Option Plan B [Member]
Share-based plans outstanding [Abstract]
Number of options awarded (in shares)	819,000
Contractual life of options	10 years 6 months
Stock Option Plan C1 [Member]
Share-based plans outstanding [Abstract]
Number of options awarded (in shares)	6,775,250
Vesting conditions	4 years
Contractual life of options	10 years
2016 Share Option and Incentive Plan [Member] \| Executives and Directors [Member]
Share-based plans outstanding [Abstract]
Number of options awarded (in shares)	257,916
Vesting conditions	4 years
Contractual life of options	10 years
2016 Share Option and Incentive Plan [Member] \| Employees [Member]
Share-based plans outstanding [Abstract]
Number of options awarded (in shares)	18,850
Vesting conditions	4 years
Contractual life of options	10 years